1. Technical Field
The present invention relates to a USB composite device, a USB communication system, and a USB communication method, and more specifically to a USB composite device, a USB communication system, and a USB communication method, in which, among plural devices having different USB subclasses, devices having the same USB subclasses are assigned to the same logic interface and a host is allowed to communicate with each device with a communication command corresponding to the device for a corresponding logical unit of the logic interface.
2. Related Art
There has been known a complex machine including devices such as a printer, a scanner, and a facsimile machine and connected to a host such as a personal computer. For example, Patent Document 1 discloses how such a complex machine is connected with a personal computer through a USB (universal serial bus) interface and the personal computer controls functions of each device of the complex machine.
Further, in recent years, there has been proposed a method of adding a device to which a memory card or other such storage media can be inserted, such as a memory card reader/writer to a complex machine of this type, and connecting a host to the complex machine through a USB interface to allow the host to transmit/receive data to/from the storage medium inserted into the complex machine. To be specific, plural logic interfaces conforming to the USB standards are set for a single physical interface, and devices such as a printer or a memory card reader/writer are assigned to the logic interfaces to thereby allow the host to identify a device to every logic interface and transmit/receive data to/from the device.
[Patent Document 1]
Japanese Unexamined Patent Application Publication No. 2003-198779